KA-38 questions

[mike-stroz]

I’m almost finished with my project Johnson KA-38 that I bought last year. I just have a few questions about the final few things that need to be addressed before I can hopefully use it. I’d like to use it regularly on my 14′ aluminum rowboat on Lake Sacandaga in NY when it’s done.
1. What is the best way to clean out the crud in the tank?
2. Should I worry about the water pump? I haven’t torn into the lower unit and I don’t really want to unless necessary (it all seems to be in very good shape).
3. What should I use to fill the lower unit, grease or oil?
4. What plug wires should I use? I’m not a stickler for originality, I just want a nice reliable motor.
5. When the time comes, what is the right fuel mix to use?

[kevinrude]

Well, let’s see if I can help a bit. I have a couple of KD-15’s, which are the post-war version of the KA’s.

1. Rinse it out the best you can with soap and water. This will get out the big pieces and the loose pieces. Next, plug up the lower outlet with a pipe fitting plug available at your local hardware store. Then, fill the tank about 1/2 way with ammonia, drop in a couple dozen nuts (also available at your local hardware store), put the gas cap on. Proceed to shake and rotate the nut/ammonia mixture. This may take several days depending on how crudded up your tank is. When done, empty the tank, rinse with water again, then rinse with denatured alcohol which prevents rusting by, I believe, absorbing the water you used to rinse the tank.

2. I mean, the motor is almost 80 years old and if the water pump parts are original, you probably do want to replace them. That being said, I haven’t gotten in to my lower unit yet, so I don’t know what type it is. Couldn’t find the information in any of my old manuals either. Weird. I will look harder.

3. Manual says 9 oz. of GREASE.

4. Standard replacement wire, available at vintage outboard parts suppliers, should suffice.

5. Manual says 1 pint per gallon of SAE #40, so that’s 8:1 (thick!)

Anything that I’ve said wrong above will be corrected shortly.

Good Luck!!!

[eltoquad]

I don’t think the KA-38 used a water pump. Prop and forward motion forced water thru the cooling system.

[Mumbles]

Since they don’t have a water pump and rely on boat movement and the propeller to force cooling water thru them, there is a way to test run them on a stand. On the bottom of the cylinder is a fitting or plug which can be removed and a fitting for a garden hose can be installed instead. They need the 8:1 mix because of the large rotary valve on the crankshaft. John Deere Cornhead Grease or Lubriplate will work in the gearcase. They have cork type seals on the prop and drive shafts which are probably worn out by now but the prop shaft bearing housing can be machined to accept a modern lip type oil seal. I did this on my KA 37 so I can use gear oil instead of grease.

http://www.greenpartstore.com/John-Deer … 02562.html

Here’s the outer half of the rotary valve showing the grooves where the sealing rings fit in.

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[kevinrude]

quote eltoquad:

I don’t think the KA-38 used a water pump. Prop and forward motion forced water thru the cooling system.

Yeah, I got curious and went and took apart the lower unit of my KD-15 parts motor. You are correct, no pump!

[mike-stroz]

Wow! That KA you’ve got is gorgeous Mumbles! I wish mine looked that good. I think the seals on my lower unit are surprisingly still good, no signs of leakage at all, and no water came out when I took out the drain plug. It looks like I’ll be able to have it up and running as soon as the snow melts.

[Mumbles]

The KA 38 in the picture isn’t mine. I found it on the interweb somewhere.

I’m waiting for some warm weather so I can put the decal on my KA 37 tank. Then it will be finished and I’ll post some pics! 😀

[mike-stroz]

Can’t wait to see it! I’ll try and post some pictures of mine when it’s back together. Not much of a looker, but it appears to be all original right down to the Champion 7 spark plugs! I think I’ll leave it all dirty like it was just pulled out of the barn.

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